Fishing leader



z July 3, 1951 J. L. MaCALLlsTER FISHING LEADER Filed April 10, .1948

IN V EN TOR.

Patented July E3, 1951 UNITED STATES PATENT OFFICE FISHING LEADER JohnL. MacAllister, Pasadena, Calif.

Application April 10, 1948, Serial No. 20,299

4 Claims.

My invention relates to a means and method of producing taperedfilaments, and the invention is particularly adapted for the productionof tapered filaments of any length or taper ratio composed of filamentforming synthetic linear polymers such as, for example, nylon.

I am aware of the fact that attempts have heretofore been made toproduce tapered filaments from synthetic linear polymers such as thelinear polyamides but these filaments have been made by drawing thematerial at varying speeds as it is extruded, with an after processingsuch as cold stretching to set the filament. Such methods appear to besatisfactory for short, and relatively thick, filaments such as might beused for brush bristles, for example, but have not been entirelysuccessful for the production of very long tapered fishing leaders, forexample.

Accordingly, it is an object of the present invention to provide a meansand method of making tapered filaments of the linear polymers of anylength and with any taper ratio, or combinations thereof, from filamentshaving a uniform diameter.

As the method of the present invention as utilized for producing taperedfilaments does not change the molecular structure or strength of thematerial as originally drawn, it is another object of the presentinvention to provide a means and method of producing tapered filamentsfrom linear polymers wherein the strength per unit cross sectional areais substantially the same throughout the filament extent.

In broad terms as to method my invention comprises etching linearpolymer filaments having a substantially level characteristic in acorrosive acid. The surface of the filament exposed to the acid isetched or dissolved away and the length of time a given portion of thefilament is exposed to the acid determines the amount of materialre'noved, providing a constant temperature is maintained. The methodadditionally comprises the control of the degree of etching byregulating the temperature of the etching acid. and cleaning thefilament after etching.

Other objects and advantages of my invention will be apparent from theensuing description of the drawings in which:

Figure 1 is a diagrammatic side view partly in section of one form ofapparatus suitable for producing long tapered filaments suitable forfishing leaders, for example.

Figure 2 is outline drawings of several types of taper reproducible bythe means and method of the present invention.

Referring to Figure 1, a tube I, such as an iron pipe, is sealed at thebottom thereof and is filled with an acid IA corrosive to the linearpolymers, such as, for example, phenol of about 88% strength, to adistance equal to the taper desired. An 88% strength phenol means 88%phenol to 12% water. The acid is preferably maintained at asubstantially constant temperature as by an oil bath 2 heated by anelectrical heater 3 under the control of a thermostat 4. The acid invertical tank I is readily heated by connection and may be heatinsulated if desired.

vIt should, however, be pointed out that the fumes from the phenol arehighly corrosive and dangerous to breathe. For that reason the exposedphenol surface should be as small as practical and convenient meansshould be provided from a safety standpoint to remove the fumes from theenclosure in which the tank is being used.

With the tank. acid heated to at least over F. to provide a practicaletching time, from one to twenty filaments 5 as, for example, of level.017 nylon nine feet long are weighted as by iron weight 6 at the bottomthereof are suspended ovei the tank from a cord 'I leading to a drum 8controlled by a reversible variable speed motor 9. For clarity ofillustration only one filament is shown.

To produce a continuous taper on the filament, the filament is immersedprogressively by action of motor 9. With a feed into the acid ofapproximately one and one half feet per minute, a taper of the .017stock to a tip diameter of .007 has been produced on nine foot lengthsat an acid temperature of approximately F. After the leader becomesfully immersed it is quickly removed.

Upon removal, the tapered filament will be found to be covered withajelly-like residue which is removed to expose the final surface of thetapered filament. As this residue' hardens on exposure to water, forminga hard scum, water containing Cleansers is to be avoided. Alcohol or aweak alcohol-phenol solution may be used, but I prefer to exclude bothair and water by immediately immersing the filament in mineral oil. Thismay be done by use of a tank similar to tube I. The residue is thenreadily wiped off the filament, revealing a surface closelyapproximating the original filament except that it is dulled due to theetching. This low reflection characteristic is highly advantageous forfishing leaders as will be pointed out later.

It will be noted that there is no significant stress applied to thefilament during the etching process and in consequence there is nochange in strength of the leader relative to unit cross sectional areasifi/any part of the leader. At the present time I have not determinedwhether or not the removed material is dissolved in the acid or is sochanged as to be readily removed after treatment. In any event, tapersare reproducible as to time and temperature of the etch.

In this respect, any desired taper, or combination of tapers, can beproduced from filaments having level characteristics by varying timeand/or temperature of etching as shown in several examples in Figure 2.Here taper A is produced by varying the immersion rate. Taper B isproduced by varying the immersion rate and then looping the filament toimmerse both ends. Taper C represents a heavybristle with one end onlytapered.

As pointed out, I am unable to state what the l reaction between thephenol and the filament may be. Experiment has shown, however, that partof the material is released from the filament into the etching fluid andpart of the material in a changed form remains on the filament in acondition to be wiped off to expose the unchanged polyamide surface atthe full depth of etching, if not subject to atmospheric contact for toolong a time. The material separated from the main body of the polyamideeither into the etching fluid or into the adhering residue has beenfound to be highly inflammable, and suitable precautions should be takento prevent ignition of this material.

As the etched surface of the tapered filaments has a dull finish, theyprovide ideal characteristics for under water use in fishing.l As thesurface layers of the etched material have not been weakened by theetching process, as would happen if the surface finish were to be dulledby scratching with an abrasive, I do not desire to be limited solely toa tapered filament having an acid etched surface. The etching can beperformed to leave a level filament with the desired dull finish byrapid immersion and withdrawal of the filament from the etchingsolution, by immersion parallel to the surface of the etching solution,or by progressing a continuous filament lshown thevetched filamentsFurthermore, while I have described my invention asbeing appliedtorelatively long tapered filaments of relatively small diameter, I donot desire to be limited thereto as heavier stock can be etched toprovide tapered bristles for paint brushes or the like for examplefollowing the invention described and claimed herein.

While I have also described the method of my invention as being appliedprimarily to filamentary bodies, it is similarly adaptable for use tochange a dimension or surface condition of bodies of other shapes.Bevels, for example, can readily be made on edges of thin sheets of thelinear polyamides or internal areas of thin sheets or other bodies canbe etched uniformly or differentially to change a desired dimension orto provide a dull surface.

I claim:

1. The method of tapering a level linear polyamide filament comprisingimmersing said filament in an etching acid and varying the amount ofetch by varying the immersion time along the length of said filament totaper said filament.

2. Method in accordance with claim 1, including the step of heating saidetching acid to approximately F. to increase the speed of the etchingaction on said filament.

3. The method of tapering a linear polyamide filament which comprisesimmersing said fila` ment in an etching acid for times varying along thelength of said filament to produce the desired taper and wiping off anetching residue to expose the tapered surface.

4. The method of tapering a linear polyamide:

filament which comprises immersing said filament in an etching acid fortimes varyingl along the length of said filament to product the desiredtaper, withdrawing said filament, coating said withdrawn filament with amineral oil, and wip# ing off said oil and etching residue adhering to'said filament.

. JOI-IN L. MACALIJSTER.

REFERENCES LCITED The following references are of record in the Y fileof this patent:

UNITED STATES PATENTS Number Name Date 1,260,395 Keller Mar. 26, 19181,935,203 Dreyfus I Nov. 14, 1933 2,188,332 Carothers Jan. 30, 19402,207,156 Neville July 9, 1940 2,207,158 Neville July 9, 1940 2,216,406Austin -Oct. 1', 1940 2,251,508 Watson Aug. 5, 1941 2,267,790 DickieDec. 30, `1941 2,370,112 Truitt Feb. 20, 1945 2,281,837 Ford May 5, 1942

